DR30 / MR30 Hatch rear ends

[discopotato03]

Adam,

The basic arm is IDENTICAL, it mounts to the same place, they are both interchangeable, BUT as Ben says, the rear brakes on the MR are different, they are only 254 instead of 290, the caliper mounts may be different as well.

The DR rear arms are unique as the HR's are same as MR & I just chucked a pair out yesterday. The original arms off my PNV, gone to the recyclers.

I have a pair of stock HR calipers here as they are very similar to DR. I will check tomorrow if the calipers can be mounted to the DR rear end etc and advise further.

<{POST_SNAPBACK}>

I think you'll find that the DR rear calipers have longers "ears" on them to space further out on the edge of the 290mm disc . I had a DR and MR caliper side by side 4 yrs ago and that seemed to be the obvious difference - aside from DR's larger diametre pistons . I did once see a 280ZX that had the large piston bridge section with the short leg non floating part so obviously can mix and match . Off the top of my head it was a 3/78 build and also had short leg big piston front calipers and the single rear mount R200 diff .

[Adam_RSX]

I was thinking that maybe one calliper would be different to allow them to both mount on the same arms, if you could have a look Ghostrider it would be much appreciated. Thanks Adrian aswell.

[Adam_RSX]

Bought a DR30 arm from Jaustech, $220!!!!!!! But it seems to be straight and I know it will fit

[Ghostrider]

faaaaaaaaaaaaaaaaaaaaa out $220.00 for one arm. Shit they're expensive, we chuck stock MR ones out here in Sydney

And my last purchase of a complete rear end minus diff was only about $400.00 and we got brakes as well.

[Adam_RSX]

Yeah... but its going now...

Are rear brake pads available for the DR brakes? Mine are almost shagged.

Alternator is on the way out aswell I think

[Boof]

Shit Adam thats expensive!! OUCH even!!!!!

Rear brake pads NFI, maybe speak with Barry or someone similar, cause you can't walk into sprints or repco and get anything for your car trust me, they have no idea what a dr is...

Alternator, either get it rebuilt or bosch one's fit, ask Josh he's replaced his with a bosch one, i just got mine rebuilt seems alright so far...

What motor you end up putting in the car??????

[Matty T]

Are rear brake pads available for the DR brakes?  Mine are almost shagged.

<{POST_SNAPBACK}>

Even if they aren't, you can get pads cut to size for about $20. Any place that sells performance brake pads should be able to line it up for you. Just take in your old backing plate for them to use as a template.

Did you end up sussing out whether the DR arms are the same as MR ones? Measure the distance from the bearing housing to the centre of one of the caliper mount holes. Take a picture of it too if you can. Either post it up here or email it to me. We'll sort this out once and for all...

[discopotato03]

Actually DR30 are same pads as rear disk MR30 and I think same as S14/S15 . Like I said the calipers are almost the same except piston size , leg length and minor variation in cable mount .

Cheers A .

[Matty T]

Actually DR30 are same pads as rear disk MR30 and I think same as S14/S15 . Like I said the calipers are almost the same except piston size , leg length and minor variation in cable mount .

Cheers A .

<{POST_SNAPBACK}>

If that is the case, the MR and the DR trailing arms are the same. Hopefully, Adam will do a little measuring and we can put this puppy to bed.

[DR JOSH]

Rear pads are the same as MR30 hatch but different to sedan. If ya want the part number for a alternator I dare say I can have a look at mine for ya seeing as how it's just laying on the floor in the garage.

And geez it looks like jaustech have up'd there prices last one I bought was $170.

Edited October 6, 2005 by DR JOSH

[Adam_RSX]

I can measure my damaged arm next time I'm at my old mans but I've been driving the car for a day now... all done

[Adam_RSX]

Same as MR30 hatch pads.... awesome

Oh, and I went to fit my 15*7 +11 Longchamps today.... Back was fine, front missed the strut by a mile but doesnt clear the callipers

[Ghostrider]

MR/HR/DR30 along with S13 rears disk pads all same, but MR30 sedans would be a problem as they have DRUM rears.

I finish early tomorrow but I think Adrian is correct as I think it's just the legs, but I will measure mine tomorrow afternoon, as I have both HR & DR rear calipers.

Adam, check the cost of Alternators Vs postage, cause Bluebird (Bosch) are same mounts & I might just have a few laying around.

Cheers

[discopotato03]

You'll find I'm right because I've been there , yes DR30 brakes bolt up to disk brake A arms with the matching disk . Because the front calipers on DR30's also use larger piston calipers the master cylinder size is larger to cope with the increased fluid transfer volume . You can get these larger 1" bore masters as some 78 model 280ZX's used them .

Cheers A .

[Ghostrider]

You'll find I'm right because I've been there , yes DR30 brakes bolt up to disk brake A arms with the matching disk . Because the front calipers on DR30's also use larger piston calipers the master cylinder size is larger to cope with the increased fluid transfer volume . You can get these larger 1" bore masters as some 78 model 280ZX's used them .

Cheers  A .

<{POST_SNAPBACK}>

Only one problem with this theory. All are not as they seem. Only 81/83 models of DR had 1" m/cylinders, all 84/85 models have only 15/16 same as Z31 300ZX.

Reason, the early models had a distribution block on top of the booster and late models had the distribution in the m/cylinder.

If owners of late models want to re make all their brake bundy tube lines, go ahead, the 1" cyl is available from any reputable brake service centre, but you must specify TOKICO as the brand.

As for the rear trailing arm issue, the parts list shows a GT and L24E rear arm, 2 different part numbers. They also list a pre 08/81 arm that is superseded by the post 09/81 arm.

Having said that, the 2 calipers are as disco says, the DR's have longer legs by about 22 odd mm to compensate for the larger rear rotor. 254 vs 290. The mount centres are identical.

As seen in pic below

Cheers,

Dennis

[discopotato03]

Interesting Dennis , I've never seen a DR30 that had the late type master/booster like late MR30's .

I've got a feeling DR A arms may have slightly different pivots and cross member , no proof just seen people screw it up when mixing arms and crossmembers . Grp A cars used unique works parts , a friend has the parts list and diagram and no I cant get at it .

[Ghostrider]

I have DR & HR rear cross members and both are identical, exact same everything, rear trailing arm mounts etc etc.

I have never compared MR to DR or HR arms, but know for sure the MR Hatch rear end is completely interchangeable with the same in a sedan, as I supplied a complete MR Ti Hatch rear to a guy in SA and he now has it in his sedan.

The parts list I have is for R30 82 on, but lists the coupe parts as well as sedan & hatch & van.

I only have DR rear arms here as I never gave it a thought that they could be different. anyhow they have calipers etc attached and they are my spares.

AS for the brakes, I may be shooting my mouth off again, but my PNV is an 84 model and it has the late model m/cyl same as MR & Z31's so I assumed all late model cars would be the same.

I also have a DR TOKICO booster and m/cyl which are the older style as you speak of. I think I took all the bundy tubing off my original MR hatch so I might just do the 1" upgrade as well. Surely it must be better for when I do the GTR conversion.

I have read where they recommend a 1" m/cyl with the 4 & 6 pot AP conversions they're now doing for Z cars.

[Ghostrider]

Geez I must have been tired last night.

The 2 different part numbers for the rear trailing arms are #1 for the L24E Sedan (DRUM brakes) and #2 for GT version (DISC brakes)

I would conclude from this, that all disc brake rear trailing arms, either MR, DR or HR would be identical.

[Ghostrider]

Interesting Dennis , I've never seen a DR30 that had the late type master/booster like late MR30's . 

I've got a feeling DR A arms may have slightly different pivots and cross member , no proof just seen people screw it up when mixing arms and crossmembers . Grp A cars used unique works parts , a friend has the parts list and diagram and no I cant get at it .

<{POST_SNAPBACK}>

A,

Let's not get into a slinging match with this because it's getting a bit off topic, but as my memory recalls, the Gibson Motorsport cars driven by Glenn Seton & George Fury had very unique works parts in them.

So unique in fact that GMS had to make everything themself as they had little support from Japan as can be seen in the #30 car now owned by Terry Ashwood that ZOOM magazine did quite an extensive article on. The entire rear end is rose joints and bars from memory, to the point that they had to make their own solid 22mm half shafts to handle the power they were putting to the ground.

Dennis

[Matty T]

Sorry to dredge this back up again, but...

1. Does anyone know a part number / vehicle that I can get a 1" master cylinder off that fits the R30 booster? Sorted.

2. Does anyone have a pair of DR30 rear calipers and discs that they are willing to sell / loan me?

Warning: Long-winded, boring background information below

My DR came with the 250mm front brakes, 254mm rear brakes and a 7/8" master cylinder. I do't know if the importer / other persons took the goodies out of it, but it also had an open diff. I competed in it once (it is a rally car) and the brakes were on fire at the end of every stage. Literally, there was smoke and flames all over the place. The pads were sensational - Mintex 1155 all round - but the brakes themselves were obviously too small.

I got a set of DR30 struts and calipers, and heavily modified the struts, so now I can't go back (not that I would want to), but I still have the small back brakes. Oh, and I couldn't get brake pads in time, so I had to run Bendix (or is it Ferodo?) Advance - crap anyway. By the way, walk into any Recpo or AutoBarnPro and ask for Aussie-delivered Z31 300ZX front disc pads. Identical to DR30 front.

I then competed in it again. Didn't really notice much difference, except that the pedal went down much further, particularly once they were hot. Oh, and I had bugger-all rear bias, so the car just wanted to understeer off the road at any opportunity!

I figured I would start by getting the 1" master cylinder. No matter what I do, this needs to be upgraded. For the life of me, I cannot get it. The biggest Tokico (or any other) one I can get is a 15/16". There is a 1" Tokico master cylinder for the Nissan Patrol (disc/drum), but it doesn't fit onto the master cylinder. Not without some time on a lathe, anyway. I just don't fancy having to machine down something if there is something out there that someone knows fits.

In order to establish some adjustability to the brakes, I am installing a pressure limiting valve. This will only be effective if I can get enough pressure to the rear calipers, so in addition to the 1" master cylinder, I need either a) the DR rear calipers and discs, or cool.gif to gut the bias block, or c) both a and b.

I have a set of 4 piston front calipers / discs, and 2 piston rear calipers / discs off an R32 GTS-T sitting here, but the conversion is just a little too yucky for me at the moment. I can only run a maximum of 15" rims, and while they will clear, I will be forced to use spacers, which will probably then require me to buy another 10 wheels that fit (factory S13 Silvia rims spring to mind). While I may be an idiot, I am not a rich idiot...

Anyone? Anyone? Bueller?

Cheers,

Matt

Edited November 11, 2005 by Matty T